(1) Field of the Invention
The invention relates to a mechanical transmission, and more particularly a mechanical transmission that is truly continuously variable.
(2) Description of the Prior Art
The most common mechanical transmission in use today is the sliding gear transmission. It is a very efficient mechanism, but is incapable of automatically changing the speed ratio without manually changing gears. Most power sources can operate only over small speed range with good economy and power. As a result, a large number of gear changes are required for efficient operation.
The present automatic and manual transmissions in use attempt to maximize operating economy and power through a constant maintenance of power source rotational speed at the top of the power curve. These transmissions do not have high efficiency or smooth operation because they must have stepped speed ratio changes. Various types of transmissions utilize braking or slipping actions to accommodate speed rate change. These transmissions generate high internal power losses.
Existing designs for continuously variable transmission such as xe2x80x9cVxe2x80x9d belt transmissions, Hydraulic transmissions and mechanical planetary gear and variable length lever transmissions lack efficiency, simplicity of operation, power transmission capability or operating speed range.
The object of the present invention is to have a continuously variable mechanical transmission system. The step less ratio change takes advantage of the fact that a hemisphere rotating around its polar axis has larger length of circumference at its major diameter than close to its tip, because the radius of a hemisphere is a constant the transition from the major diameter to a minor produces step less length of circumference change without changing the point of engagement between the hemisphere wheel and a second wheel. The present invention can be adapted to any mechanical variable output device. The hemisphere wheel thus would be mounted on the bearing. The inside race of the bearing would have two pivot points inside the wheels major diameter, allowing the wheel to swing around the mounting fork, the fork is attached to the wall of the transmission. The center of the hemisphere wheel would be connected to the driving shaft through a constant velocity device (double universal joint, flexible shaft or similar). Alternatively, a motor can be mounted on the inner race of the bearing with its shaft attached to the hemisphere wheel thus eliminating the need for a constant velocity device.
A control lever would have a joint attachment to the inner race of the wheel bearing, perpendicular to the pivot points. Movement of the control lever would swing the hemisphere wheel around the pivot points, therefore changing the engaged diameter of the wheel. The position of the control lever would determine the transmission rate. If a double universal joint is used to connect the driving shaft to the hemisphere wheel, the maximum swing angle of the wheel can be 70 degrees. At this angle of the wheel, the transmission rate will be 2.8 times less then when the angle is equal to zero and the hemisphere wheel is engaged at its major diameter. The second wheel of the transmission can be a regular narrow wheel or another hemisphere wheel similarly mounted and attached to the second shaft.
It is therefore an object of the present invention to provide an improved continuously variable mechanical transmission system which can be easily and economically produced, simple in principal, convenient in operation, sturdy in construction, highly efficient, long lasting and capable of operating under wide range of power and speed. It is another object of the invention to have a transmission with ratio of input to output that can be varied instead of fixed.
It is a further object of the present invention to have a continuously variable transmission system comprising: an input shaft is a flexible constant velocity device connected to a hemisphere wheel on the inside center of said hemisphere wheel. The hemisphere wheel having a bearing. A housing of the transmission having a mounting fork attached to the hemisphere wheel at two pivot points on the inner race of the bearing located on the inside circumference at the hemispheres major diameter. Further having a control lever with a joint attachment to the inner race of the bearing that is perpendicular to the pivot points of the mounting fork; and having an output shaft connected to a second wheel, and the second wheel""s circumference engaged with the outside of said hemisphere wheel. Finally, the control lever having the ability to swing the hemisphere wheel around the pivot points of the mounting fork to change the engaged diameter of the hemisphere wheel such that the difference in diameter from equator to pole creates a continuously variable transmission.